Five-degree-of-freedom hybrid magnetic bearing, motor and control method thereof

Abstract

The application provides a five-degree-of-freedom hybrid magnetic suspension bearing, a motor and a control method thereof. The magnetic suspension bearing comprises an axial stator core, front and rear radial stator cores, first and second permanent magnet rings respectively arranged between the radial stator cores and the end portions of the axial stator core, an axial stator sleeve coaxial with a rotating shaft, a first thrust disc and a second thrust disc formed in the rotating shaft, a group of axial control coils arranged in the annular space between the first thrust disc and the second thrust disc, and the axial stator sleeve of the axial stator core arranged in the annular space. The first axial bias magnetic circuit formed by the first permanent magnet ring has a direction opposite to the second axial bias magnetic circuit formed by the second permanent magnet ring in the first thrust disc and the second thrust disc. The application can realize the adjustment control of the axial position of the thrust disc by controlling only the group of axial control coils, the control logic is simpler, the length of the corresponding rotating shaft can be shortened, and the rotating speed of the rotating shaft is improved.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation bearing design technology, specifically relating to a five-degree-of-freedom hybrid magnetic levitation bearing, a motor, and a control method thereof. Background Technology

[0002] Magnetic levitation bearings are a new type of high-performance bearing that uses magnetic force to levitate the rotor in space. Since there is no mechanical contact between the stator and rotor, there is no wear or lubrication, so they are particularly suitable for special applications such as high speed, vacuum and ultra-clean environments. They are a high-tech product that integrates electromagnetics, electronic technology, control engineering, signal processing and mechanics.

[0003] A free rotor in three-dimensional space has six degrees of freedom: three translational and three rotational. To achieve normal operation of the suspended rotor, stable control of the remaining five degrees of freedom, in addition to rotational motion, is necessary. The applicant previously proposed a low-power permanent magnet biased five-degree-of-freedom integrated magnetic bearing (publication number CN10615331A). Specifically, a magnetically shielding aluminum ring is placed between the left and right axial magnetic bearing cores; control coils for the left and right radial magnetic bearings are wound in the stator slots of the left and right radial magnetic bearing cores, respectively; both the left and right axial magnetic bearing cores have an E-shaped structure, and control coils are wound in the stator slots. This invention effectively solves the shortcomings of existing five-degree-of-freedom magnetic levitation systems, providing a low-power permanent magnet biased five-degree-of-freedom integrated magnetic bearing that is small in size, light in weight, short in axial length, high in critical speed, high in core utilization, simple in structure, manufacturing and assembly, and whose axial and radial control magnetic fluxes do not pass through permanent magnets, and can generate greater axial and radial levitation forces. However, this five-degree-of-freedom levitation system, which uses two radial electromagnetic bearings and one axial electromagnetic bearing to replace mechanical bearings to control the rotor, has two sets of axial control coils, one on the left and one on the right, respectively, located on the left and right sides of the thrust plate. At the same time, there are two sets of radial magnetic bearing cores on each side of the axial magnetic bearing core. This makes the axial length of the five-degree-of-freedom magnetic bearing too large, resulting in a correspondingly large shaft length in the shaft system in which it is used, which limits the speed increase and makes the control more complex. The opposing structure of the two sets of axial control coils also requires the use of magnetic isolation rings to isolate the magnetic circuits of the two axial cores to reduce magnetic leakage, which makes the structure of the magnetic bearing relatively complex. More importantly, when the aforementioned technical solution is applied to the shaft of two thrust discs with axial spacing, two sets of axial magnetic bearings are required, which will occupy a larger axial dimension. How to shorten the magnetic levitation bearing that matches the shaft with dual thrust disc bearings is an urgent problem to be solved. Summary of the Invention

[0004] Therefore, the present invention provides a five-degree-of-freedom hybrid magnetic levitation bearing, a motor and a control method thereof, which can solve the technical problem in the prior art that the five-degree-of-freedom hybrid magnetic levitation bearing matched with a shaft with dual thrust disks needs to have corresponding axial coils on both sides corresponding to the left and right sides of each thrust disk, resulting in a large axial dimension of the magnetic levitation bearing.

[0005] To address the aforementioned problems, this invention provides a five-degree-of-freedom hybrid magnetic levitation bearing, comprising an axial stator core and a front radial stator core and a rear radial stator core located at opposite axial ends of the axial stator core. A first permanent magnet ring is disposed between the ends of the front radial stator core and the axial stator core, and a second permanent magnet ring is disposed between the ends of the rear radial stator core and the axial stator core. The axial stator core includes an axial stator sleeve coaxial with the rotating shaft. The rotating shaft has a first thrust disk and a second thrust disk forming an annular gap. The axial stator sleeve is located within the annular gap. Only one set of axial control coils is disposed within the annular gap, and the axial control coils are arranged around the rotating shaft. The direction of the first axial bias magnetic circuit formed by the first permanent magnet ring within the first thrust disk is opposite to the direction of the second axial bias magnetic circuit formed by the second permanent magnet ring within the second thrust disk.

[0006] In some embodiments, a first space is formed between the front radial stator core and the first end of the axial stator core, the first thrust disk is located within the first space, and the front radial stator core is fitted radially outside the first thrust disk with a gap; a second space is formed between the rear radial stator core and the second end of the axial stator core, the second thrust disk is located within the second space, and the rear radial stator core is within the length range covered by the second thrust disk.

[0007] In some embodiments, the five-degree-of-freedom hybrid magnetic levitation bearing further includes a first connecting magnetic ring and a second connecting magnetic ring. The first permanent magnet ring and the second permanent magnet ring are respectively fitted onto the two ends of the axial stator sleeve. The first connecting magnetic ring is fitted onto the outer circumferential wall of the first permanent magnet ring, and the second connecting magnetic ring is fitted onto the outer circumferential wall of the second permanent magnet ring. The front radial stator core is connected to the inner ring wall of the first connecting magnetic ring, and the rear radial stator core is connected to the inner ring wall of the second connecting magnetic ring.

[0008] In some embodiments, the axial section of the first connecting magnetic ring and the second connecting magnetic ring includes a first radial segment extending radially outward along the axis of rotation and a first axial segment extending axially along the axis of rotation, the first axial segment being connected to the radially outer end of the first radial segment to form an L-shape.

[0009] In some embodiments, the two ends of the axial stator sleeve each have an axial stator connecting core extending radially outward along the axis of rotation, the first permanent magnet ring is located between the front radial stator core and the axial stator connecting core at the first end of the axial stator sleeve, and the second permanent magnet ring is located between the rear radial stator core and the axial stator connecting core at the second end of the axial stator sleeve.

[0010] In some embodiments, the axial section of the axial stator connecting core includes a second radial segment extending radially outward along the axis of rotation and a second axial segment extending axially along the axis of rotation, the second axial segment being connected to the radially outer end of the second radial segment to form an L-shape.

[0011] In some embodiments, the five-degree-of-freedom hybrid magnetic levitation bearing is an inner rotor structure or an outer rotor structure; and / or, the inner or outer ring wall of the axial stator sleeve has a receiving ring groove, and the axial control coil is wound and assembled in the receiving ring groove.

[0012] The present invention also provides an electric motor, including a shaft, said shaft being supported on at least one of the above-described five-degree-of-freedom hybrid magnetic levitation bearings.

[0013] The present invention also provides a control method for a motor as described above, comprising the following steps:

[0014] The first minimum distance da between the first thrust disc and the first end face of the axial stator sleeve and the second minimum distance db between the second thrust disc and the second end face of the axial stator sleeve are obtained respectively.

[0015] Based on the relationship between da and db, the direction and / or magnitude of the current in the axial control coil are adjusted so that the shaft moves axially toward the side with the larger value between da and db.

[0016] In some implementations, adjusting the current direction and / or current magnitude in the axial control coil according to the relationship between da and db to move the shaft axially toward the side with the larger value of da and db specifically includes:

[0017] When da > db, the current direction in the axial control coil is controlled to be a first direction so that the control magnetic circuit generated by the axial control coil is superimposed in the same direction as the permanent magnet bias magnetic circuit generated by the first permanent magnet ring, and is reduced in the opposite direction to the permanent magnet bias magnetic circuit generated by the second permanent magnet ring, thereby controlling the magnitude of the current in the axial control coil to become smaller and smaller; or...

[0018] When da < db, the current direction in the axial control coil is controlled to be the second direction so that the control magnetic circuit generated by the axial control coil is reduced in the opposite direction to the permanent magnet bias magnetic circuit generated by the first permanent magnet ring, and superimposed in the same direction with the permanent magnet bias magnetic circuit generated by the second permanent magnet ring. This controls the magnitude of the current in the axial control coil to become smaller and smaller, with the first direction being opposite to the second direction; or...

[0019] When da = db, the direction and / or magnitude of the current in the axial control coil remain unchanged.

[0020] This invention provides a five-degree-of-freedom hybrid magnetic levitation bearing, motor, and control method. By setting only one set of axial control coils coaxial with the rotating shaft in the annular interval, the magnetic flux can be canceled or superimposed by utilizing the directional differences between the permanent magnet bias magnetic circuit and the axial control magnetic circuit. This allows for the adjustment and control of the axial position of the thrust plate by controlling only one set of axial control coils, simplifying the control logic. Furthermore, since only one set of axial control coils is used, there is a smaller axial space requirement. The shaft length of the magnetic bearing matched with the rotating shafts of the two thrust plates can be designed to be smaller, thereby shortening the corresponding rotating shaft length and increasing the rotating shaft speed. More importantly, the first permanent magnet ring and the second permanent magnet ring are respectively located between the axial stator core and the two radial stator cores, which can isolate the axial control magnetic circuit and the radial control magnetic circuit, effectively reducing the coupling between the radial control magnetic circuit and the axial control magnetic circuit, further reducing the control difficulty of the magnetic bearing, that is, simplifying the control logic. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the axial section of a five-degree-of-freedom hybrid magnetic levitation bearing in one embodiment of the present invention (only half of the axial section is shown), and the arrows in the figure indicate the direction of the magnetic circuit;

[0022] Figure 2 This is a schematic diagram of the axial section of a five-degree-of-freedom hybrid magnetic levitation bearing according to another embodiment of the present invention (only half of the axial section is shown), and the arrows in the figure indicate the direction of the magnetic circuit;

[0023] Figure 3 This is a schematic diagram of the axial section of a five-degree-of-freedom hybrid magnetic levitation bearing in another embodiment of the present invention (only half of the axial section is shown). The arrows in the figure indicate the direction of the magnetic circuit.

[0024] Figure 4 for Figure 3 A schematic diagram of the axial projection, with arrows indicating the radial magnetic path direction;

[0025] Figure 5This is a schematic diagram of the axial section of a five-degree-of-freedom hybrid magnetic levitation bearing in another embodiment of the present invention. The arrows in the figure indicate the direction of the magnetic circuit.

[0026] The reference numerals in the attached figures are as follows:

[0027] 1. Axial stator core; 11. Axial stator sleeve; 12. Axial stator connecting core; 14. Axial control coil; 21. Front radial stator core; 22. Rear radial stator core; 23. Radial stator yoke; 24. Radial stator teeth; 25. Radial control coil; 31. First permanent magnet ring; 32. Second permanent magnet ring; 41. First connecting magnetic ring; 42. Second connecting magnetic ring; 100. First thrust plate; 101. Second thrust plate; 102. Rotating shaft; 201. Axial control magnetic circuit; 202. Front radial control magnetic circuit; 203. Rear radial control magnetic circuit; 204. First permanent magnet biasing magnetic circuit; 205. Second permanent magnet biasing magnetic circuit. Detailed Implementation

[0028] See also Figure 1 and Figure 5 As shown, according to an embodiment of the present invention, a five-degree-of-freedom hybrid magnetic levitation bearing is provided, including an axial stator core 1 and a front radial stator core 21 and a rear radial stator core 22 located at opposite axial ends of the axial stator core 1. A first permanent magnet ring 31 is disposed between the front radial stator core 21 and the end of the axial stator core 1, and a second permanent magnet ring 32 is disposed between the rear radial stator core 22 and the end of the axial stator core 1. It is understood that both the first permanent magnet ring 31 and the second permanent magnet ring 32 are coaxial with the rotating shaft 102. The axial stator core 1 includes an axial stator sleeve 11 (e.g., formed by stacking silicon steel sheets) coaxial with the rotating shaft 102. The shaft 102 has a first thrust disk 100 (also called rotor core) and a second thrust disk 101 forming an annular gap (not indicated in the figure). The axial stator sleeve 11 is located within the annular gap, thereby forming axial adjustment air gaps between the two ends of the axial stator sleeve 11 and the first thrust disk 100 and the second thrust disk 101, respectively. Only one set of axial control coils 14 is provided within the annular gap, and the axial control coils 14 are arranged around the shaft 102. The direction of the first axial bias magnetic circuit formed by the first permanent magnet ring 31 in the first thrust disk 100 is opposite to the direction of the second axial bias magnetic circuit formed by the second permanent magnet ring 32 in the second thrust disk 101 (e.g., Figure 1 The magnetic circuit is shown in the diagram.

[0029] In this technical solution, by setting only one set of axial control coils 14 coaxially with the rotating shaft 102 in the annular interval, the magnetic flux can be canceled or superimposed by utilizing the difference in direction between the permanent magnet bias magnetic circuit and the axial control magnetic circuit. Thus, the axial position adjustment control of the rotating shaft 102 can be achieved by controlling only one set of axial control coils 14. The control logic is simpler, and since only one set of axial control coils is set, there is a smaller axial space requirement. The shaft length of the magnetic bearing matched with the rotating shaft of the two thrust discs can be designed to be smaller, thereby shortening the corresponding rotating shaft length and increasing the rotating shaft speed. More importantly, the first permanent magnet ring 31 and the second permanent magnet ring 32 are respectively located between the axial stator core and the two radial stator cores, which can isolate the axial control magnetic circuit and the radial control magnetic circuit, effectively reducing the coupling between the radial control magnetic circuit and the axial control magnetic circuit, further reducing the control difficulty of the magnetic bearing, that is, the control logic is simplified.

[0030] In some embodiments, a first space is formed between the front radial stator core 21 and the first end of the axial stator core 1, the first thrust disk 100 is located in the first space, and the front radial stator core 21 is fitted on the radial outer side of the first thrust disk 100, forming a gap between them; a second space is formed between the rear radial stator core 22 and the second end of the axial stator core 1, the second thrust disk 101 is located in the second space, and the rear radial stator core 22 is within the length range of the second thrust disk 101. With this design, the front radial stator core 21 and the rear radial stator core 22 are respectively corresponding to the first thrust disk 100 and the second thrust disk 101, and the radial control magnetic circuits (202 and 203) correspond to the two thrust disks, making the adjustment of the radial position of the rotating shaft 102 more reliable and stable, and at the same time, the axial length of the magnetic bearing can be further shortened.

[0031] In a specific embodiment, such as Figure 1 and Figure 2As shown, the five-degree-of-freedom hybrid magnetic levitation bearing also includes a first connecting magnetic ring 41 and a second connecting magnetic ring 42 (which can be formed by stacking silicon steel sheets). The first permanent magnet ring 31 and the second permanent magnet ring 32 are respectively fitted onto the two ends of the axial stator sleeve 11. The first connecting magnetic ring 41 is fitted onto the outer circumferential wall of the first permanent magnet ring 31, and the second connecting magnetic ring 42 is fitted onto the outer circumferential wall of the second permanent magnet ring 32. The front radial stator core 21 is connected to the inner ring wall of the first connecting magnetic ring 41, and the rear radial stator core 22 is connected to the inner ring wall of the second connecting magnetic ring 42. With this design, the radii of the two permanent magnet rings can be designed to be smaller, thus saving the material cost of the magnets. Furthermore, the axial sections of the first connecting magnetic ring 41 and the second connecting magnetic ring 42 include a first radial segment extending outward along the radial direction of the rotating shaft 102 and a first axial segment extending along the axial direction of the rotating shaft 102. The first axial segment is connected to the radial outer end of the first radial segment to form an L-shape. In this way, the axial length of the corresponding thrust disk can be designed to be relatively large, which can increase the diameter of the corresponding shaft segment of the rotating shaft 102, thereby improving the overall structural rigidity of the rotating shaft 102.

[0032] In another specific embodiment, such as Figure 3 As shown, the two ends of the axial stator sleeve 11 have axial stator connecting cores 12 extending radially outward along the rotating shaft 102. The first permanent magnet ring 31 is located between the front radial stator core 21 and the axial stator connecting core 12 at the first end of the axial stator sleeve 11, and the second permanent magnet ring 32 is located between the rear radial stator core 22 and the axial stator connecting core 12 at the second end of the axial stator sleeve 11. In this technical solution, the axial stator connecting core 12 and the axial stator sleeve 11 are connected as a whole, which can be formed by integral processing (such as stamping or cutting), simplifying the assembly of the axial stator core 1. Specifically, the axial section of the axial stator connecting core 12 includes a second radial segment extending outward along the radial direction of the rotating shaft 102 and a second axial segment extending along the axial direction of the rotating shaft 102. The second axial segment is connected to the radial outer end of the second radial segment to form an L-shape. In this way, the axial length of the corresponding thrust disk can be designed to be relatively large, which can increase the diameter of the corresponding shaft segment of the rotating shaft 102, thereby improving the overall structural rigidity of the rotating shaft 102.

[0033] See also Figure 3 and Figure 4As shown, both the front radial stator core 21 and the rear radial stator core 22 include a radial stator yoke 23 (specifically a yoke ring) and several radial stator teeth 24 spaced apart along the circumferential direction of the shaft 102. Each radial stator tooth 24 is wound with a radial control coil 25, which is used to generate a radial control magnetic circuit (e.g., the front radial control magnetic circuit 202 and the rear radial control magnetic circuit 203). The first permanent magnet ring 31 is located between the radial stator yoke 23 and the end face of the corresponding second axial segment.

[0034] The axial control coil 14 can be assembled and connected (e.g., by adhesive bonding or interference fit) to the inner annular wall of the axial stator sleeve 11 using a corresponding insulating frame (or other assembly structure). Figure 1 and Figure 3 (as shown) or outer ring wall (such as Figure 5 As shown, the axial control coil 14 is entirely located in the outer region of the axial stator sleeve 11, which will not damage the structure of the axial stator sleeve 11, the magnetic circuit area will not decrease, and the magnetic reluctance is relatively small. Therefore, it will not negatively affect the orientation of the axial control magnetic circuit 201, which is beneficial for the effective control of the magnetic levitation bearing; see also Figure 2 As shown, it is different. Figure 1 , Figure 3 and Figure 5 In the structure shown, in this embodiment, the aforementioned inner ring wall has a receiving ring groove (not indicated in the figure), and the axial control coil 14 is wound and assembled in the receiving ring groove and is located on the radial outer side of the rotating shaft 102. In this technical solution, the axial control coil 14 is assembled by the receiving ring groove, which simplifies the connection structure and makes the coil assembly more reliable. As a feasible method, this method reduces the magnetic circuit area to a certain extent and increases the magnetic resistance because a receiving groove is formed on the stator core.

[0035] The five-degree-of-freedom hybrid magnetic levitation bearing in this invention has an internal rotor structure. Figures 1 to 3 (as shown) or external rotor structure ( Figure 5 As shown in the figure, this makes the application scenarios of the magnetic levitation bearing in this invention more diverse.

[0036] In a preferred embodiment, the axial stator core 1 is assembled from two mutually symmetrical core sub-body (not labeled in the figure), and the two symmetrical core sub-body facilitates the maintenance of the axial control coil 14.

[0037] According to an embodiment of the present invention, an electric motor is also provided, including a shaft 102, which is supported on at least one of the aforementioned five-degree-of-freedom hybrid magnetic levitation bearings.

[0038] According to an embodiment of the present invention, a motor control method as described above is also provided, comprising the following steps:

[0039] The first minimum distance da between the first thrust plate 100 and the first end face of the axial stator sleeve 11 and the second minimum distance db between the second thrust plate 101 and the second end face of the axial stator sleeve 11 are obtained by displacement sensors.

[0040] Based on the relationship between da and db, adjust the direction and / or magnitude of the current in the axial control coil 14 so that the rotating shaft 102 moves axially toward the side with the larger value of da and db.

[0041] In this technical solution, when the axial position of the rotating shaft 102 deviates from the preset position, its axial position can be adjusted simply by controlling the direction and magnitude of the current in a set of axial control coils 14, which greatly simplifies the adjustment control logic of the axial displacement of the magnetic levitation bearing.

[0042] In some embodiments, adjusting the current direction and / or current magnitude within the axial control coil 14 according to the relationship between da and db to cause the rotating shaft 102 to move axially toward the side with the larger value of da and db specifically includes:

[0043] When da > db, the current direction in the axial control coil 14 is controlled in a first direction so that the control magnetic circuit generated by the axial control coil 14 is superimposed in the same direction as the permanent magnet bias magnetic circuit generated by the first permanent magnet ring 31 and is superimposed in the opposite direction as the permanent magnet bias magnetic circuit generated by the second permanent magnet ring 32, thus controlling the current magnitude in the axial control coil 14 to become smaller and smaller; or, when da < db, the current direction in the axial control coil 14 is controlled in a second direction so that the control magnetic circuit generated by the axial control coil 14 is superimposed in the same direction as the permanent magnet bias magnetic circuit generated by the first permanent magnet ring 31 and is superimposed in the same direction as the permanent magnet bias magnetic circuit generated by the second permanent magnet ring 32, thus controlling the current magnitude in the axial control coil 14 to become smaller and smaller, with the first direction and the second direction being opposite; or, when da = db, the current direction and / or current magnitude in the axial control coil 14 are kept unchanged.

[0044] The radial position of the rotating shaft 102 can be adjusted according to the radial bearing adjustment method in the prior art. Since its adjustment is decoupled from the axial control magnetic circuit, it can be adjusted independently, which will not be elaborated here.

[0045] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A five-degree-of-freedom hybrid magnetic levitation bearing, characterized in that, The system includes an axial stator core (1) and a front radial stator core (21) and a rear radial stator core (22) located at opposite ends of the axial stator core (1). A first permanent magnet ring (31) is provided between the front radial stator core (21) and the end of the axial stator core (1), and a second permanent magnet ring (32) is provided between the rear radial stator core (22) and the end of the axial stator core (1). The axial stator core (1) includes an axial stator sleeve (11) coaxial with a rotating shaft (102). The first thrust plate (100) and the second thrust plate (101) form an annular gap. The axial stator sleeve (11) is located within the annular gap. Only one set of axial control coils (14) is provided within the annular gap, and the axial control coils (14) are arranged around the rotating shaft (102). The direction of the first axial bias magnetic circuit formed by the first permanent magnet ring (31) in the first thrust plate (100) is opposite to the direction of the second axial bias magnetic circuit formed by the second permanent magnet ring (32) in the second thrust plate (101).

2. The five-degree-of-freedom hybrid magnetic levitation bearing according to claim 1, characterized in that, A first space is formed between the front radial stator core (21) and the first end of the axial stator core (1), the first thrust disk (100) is located in the first space, and the front radial stator core (21) is fitted on the radial outer side of the first thrust disk (100) with a gap; a second space is formed between the rear radial stator core (22) and the second end of the axial stator core (1), the second thrust disk (101) is located in the second space, and the rear radial stator core (22) is fitted on the radial outer side of the second thrust disk (101) with a gap.

3. The five-degree-of-freedom hybrid magnetic levitation bearing according to claim 1 or 2, characterized in that, It also includes a first connecting magnetic ring (41) and a second connecting magnetic ring (42). The first permanent magnet ring (31) and the second permanent magnet ring (32) are respectively fitted on both ends of the axial stator sleeve (11). The first connecting magnetic ring (41) is fitted on the outer circumferential wall of the first permanent magnet ring (31), and the second connecting magnetic ring (42) is fitted on the outer circumferential wall of the second permanent magnet ring (32). The front radial stator core (21) is connected to the inner ring wall of the first connecting magnetic ring (41), and the rear radial stator core (22) is connected to the inner ring wall of the second connecting magnetic ring (42).

4. The five-degree-of-freedom hybrid magnetic levitation bearing according to claim 3, characterized in that, The axial section of the first connecting magnetic ring (41) and the second connecting magnetic ring (42) includes a first radial segment extending radially outward along the rotating shaft (102) and a first axial segment extending axially along the rotating shaft (102), the first axial segment being connected to the radially outer end of the first radial segment to form an L-shape.

5. The five-degree-of-freedom hybrid magnetic levitation bearing according to claim 1 or 2, characterized in that, The two ends of the axial stator sleeve (11) have axial stator connecting cores (12) extending radially outward along the rotating shaft (102). The first permanent magnet ring (31) is located between the front radial stator core (21) and the axial stator connecting core (12) at the first end of the axial stator sleeve (11). The second permanent magnet ring (32) is located between the rear radial stator core (22) and the axial stator connecting core (12) at the second end of the axial stator sleeve (11).

6. The five-degree-of-freedom hybrid magnetic levitation bearing according to claim 5, characterized in that, The axial section of the axial stator connecting core (12) includes a second radial segment extending radially outward along the rotating shaft (102) and a second axial segment extending axially along the rotating shaft (102), the second axial segment being connected to the radially outer end of the second radial segment to form an L-shape.

7. The five-degree-of-freedom hybrid magnetic levitation bearing according to claim 1 or 2, characterized in that, The five-degree-of-freedom hybrid magnetic levitation bearing is an inner rotor structure or an outer rotor structure; and / or, the inner or outer ring wall of the axial stator sleeve (11) has a receiving ring groove, and the axial control coil (14) is wound and assembled in the receiving ring groove.

8. An electric motor, comprising a rotating shaft (102), characterized in that, The shaft (102) is supported at least on a five-degree-of-freedom hybrid magnetic levitation bearing as described in any one of claims 1 to 7.

9. A method for controlling a motor as described in claim 8, characterized in that, Includes the following steps: The first minimum distance da between the first thrust plate (100) and the first end face of the axial stator sleeve (11) and the second minimum distance db between the second thrust plate (101) and the second end face of the axial stator sleeve (11) are respectively obtained; Based on the relationship between da and db, the direction and / or magnitude of the current in the axial control coil (14) are adjusted so that the rotating shaft (102) moves axially toward the side with the larger value of da and db.

10. The control method according to claim 9, characterized in that, Adjusting the current direction and / or current magnitude in the axial control coil (14) according to the relationship between da and db to make the rotating shaft (102) move axially toward the side with the larger value of da and db specifically includes: When da > db, the current direction in the axial control coil (14) is controlled to be the first direction so that the control magnetic circuit generated by the axial control coil (14) is superimposed in the same direction as the permanent magnet bias magnetic circuit generated by the first permanent magnet ring (31) and is reduced in the opposite direction to the permanent magnet bias magnetic circuit generated by the second permanent magnet ring (32), thereby controlling the current in the axial control coil (14) to become smaller and smaller; or, When da < db, the current direction in the axial control coil (14) is controlled to be the second direction so that the control magnetic circuit generated by the axial control coil (14) is reduced in the opposite direction to the permanent magnet bias magnetic circuit generated by the first permanent magnet ring (31) and superimposed in the same direction to the permanent magnet bias magnetic circuit generated by the second permanent magnet ring (32), thereby controlling the current in the axial control coil (14) to become smaller and smaller, and the first direction is opposite to the second direction; or, When da=db, the direction and / or magnitude of the current in the axial control coil (14) remain unchanged.

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